habit

crystal, aggregate, crystal fragment

acicular, bladed, dendritic, radiating, drusy, columnar, fibrous, globular, botryoidal, colloform, foliated,
micaceous, lamellar or tabular, stalactitic, concentric, banded, massive, amygdaloidal, geode, concretion
prismatic, blocky, compact, agate

How does one recognize the difference between an aggregate of crystals, a crystal fragment, and a single crystal?
Given the crystal class and a form, you should be able to find the appearance of that form in your text.
Sketch the most common crystal and aggregates habits.